Abrasive article and method of making the same



Patented Feb. 16, 1926.

UNITED STATES PATENT oFFl-cE.

mmnn L. nanruann, or nmenna FALLS, new YORK, ASSIGNOIB. no man cannonuumm oomrnmr, or nmcana runs, new YORK, A, conronarron or PENNSYLVANIA.

ABBASIV E ARTICLE AND METHOD OF MAKING THE SAME.

No Drawing.

' articles. In the art of grinding, material is removed by applying van article having anabrasive "grinding surface to the desired object. In its usual form the grinding -merapidly revolving abrasive wheel. Abrasive wheels are made up of hard particles ofcrystalline mineral material, such as silicon carbide, emery, fused alumina and aluminous materials commonly known in the trade as aloxite, alundum, and the like, held together by a bonding agent, such as fused silicates, glue, shellac,'rubber, etc..

In this specification, such abrasive appliances will'be referred to as grindin wheels. Grinding wheels consist essentially of numerous cutting oints, held in place by the surrounding a rasive particles (in the sub-surface) and the bonding medium. The extruding cutting points, as they come in contact with the material being ground,

process there is also much ineffectual friction between the surface being ground and the non-cutting po'rtionof the wheel surface. This causes frictional heat, sometimes to such an extent that water or air blasts must be used for cooling, to prevent damage to the article being abraded.

greases, resins and waxes have been used as fillers within the pores of the grinding wheel. The action of these materials depends upon their melting under the heat created by the friction, and therebybe'coming liquids at the surface of the grinding wheel and functioning as lubricants. The same effect may be and is attained by smear ing the surface of the wheel or the object being ground with a heavy viscous lubri-.

eating oil.

There are several serious defects to filled abrasive wheels as above described.

The filler may be unevenly distributed ,;dur-

dium consists of the peripheral surface of a,

Application filed January 24, 1923. Serial No. 614,683.

ing the process of impregnation, and the dynamic balance of the wheel seriously affected. This may subsequently lead to the breaking .of the wheel while in rotation, with inherent dangers. The filled wheel in action frequently throws the 'melted' grease, wax or rosin, making unhealthful working conditions. The odors invariably rising from the decomposition and burning ofthese organic filler materials during the grinding operation is one of the most serious defects.

I have discovered that all of these defects may be overcome by the use "of a solid, in-

fusible lubricating material "incorporated within the pores of the grinding wheel. In addition, the grinding efliciency is increased and the energy used in the grinding operation is decreased because the ineffectual frictional losses are decreased. The actual weight of the solid lubricating agent which need be applied in thewheels is small in comparison to the quantity usually employed in filled wheels and consequently the effect upon the balance of the grinding wheel is negligible. Since the solid lubricating agent is infusible at the tempera-- tures attained by friction in grinding operatlons, there is no smoke nor odor, nor is melted material thrown from the wheel as in the case of the grease, waxes and resins. out small chips or turnings, but in this In carrying out my invention, I may use, for example, finely comminuted graphite. It is wellknown that graphite is an excellent lubricant and that its superiorlubrie eating action is inherent in the itself and not in the vehicle or carrier with which-it is commonly used. In order to impregnate grinding wheelswith graphite, To avoid this deleterious effect, various 1 I prefer to use a suspension of finely .divided graphite in water, together with a small portion of an agglutinate, such as dextrine, which acts as a temporary binder for the graphite after the subsequent removal of the water.- The grinding wheelis' immersed in this suspension, preferably under. reduced pressure; in order to facilitate the penetration of the graphite suspension to all of the pore spaces in the wheel. After this treatment, the wheel is removed and dried and is then ready for use as an abrasive grinding wheel.

The invention is, however, not restricted graphite to the use of graphite, since othersolid infusible materials havinglubricating qualities may be used, such, for example, as finely divided talc, mica, clay, zinc stearate, and the like. Also the lubricant may be incorporated in the abrasive articles in other ways, such, for example, as dusting on a powdered lubricant. The invention is therefore not limited to its described embodiment, but may be otherwise embodied Within the scope of the following claims.

I claim: I e

1. An abrasive article having voids containing a finely divided solid-lubricating material which is infusible under the heat normally-created by the abrasive action and 'a binder for the lubricant, substantially as described.

2. An abrasive article having voids containing graphite and a binder for the graphite, substantially as described 3. The method of lubricating an abrasive article, which consists in impregnating it Will a solid lubricant, which does not melt under the heat normally created by the abrasiveaction, and a binder for the lubricant, substantially as described.

4. The method of treating formed abrasive articles having voids, which consists in impregnating the article with a liquid carrier holding a solid lubricant which does not melt under the heat normally created by the abrasive action, and thereafter removing the liquid, leaving the solid lubricant in the voids, substantially-as described.

5. The method of treating formed abra- C sive wheels, comprising dipping the wheels in water with comminuted graphite held in suspension therein, and then drying the wheels, substantially as described.

6. The method of treating formed abrasive wheels, comprising dipping the wheels in water with romminuted graphite held in suspension therein while under reduced pressure, and then drying the Wheels, substantially as described.

7. The method of treating formed abrasive wheels, comprising dipping the wheels in water with comminuted graphite and an agglutinate held in suspension therein, and then drying the wheels, substantially as described.

In testimony whereof I have hereunto set my hand.

MINER L. HARTMANN. 

